Generally, acrylonitrile-butadiene styrene-rubber (ABS) resin is widely used in electrical/electronic parts, home appliances, toy products, and office machines. ABS resins can have good processability attributed to styrene, strength and chemical resistant properties attributed to acrylonitrile, and high impact strength attributed to butadiene. ABS resins can also have a desirable appearance including gloss.
However, ABS resin contains chemically unstable double bonds in the rubber component of the resin, which can degrade upon prolonged exposure to ultraviolet (UV) radiation. Thus ABS resins can have poor weather resistance and light resistance. Therefore, when an ABS resin product is left outside for a long period, over time, discoloration and physical degradation occur, rendering the ABS resin product unsuitable for outdoor purposes. Post processing methods, such as coating or plating the ABS resin formed product, or addition of a large amount of stabilizers during the extrusion process of ABS resin, can be used to address this issue. However, the former is a complicated process with high defect rates, while the latter increases the production cost and cannot give satisfactory long term weather resistance.
To overcome the limitations of ABS resins, various weather resistant resins, such as acrylate-styrene-acrylonitrile resin CASA resin'), can be used instead of ABS resin.
Thermal resistance can also be important for various outdoor purposes, such as in automobiles. To acquire thermal resistance, α-methyl styrene, which is a styrene monomer with excellent heat resistance, and an excellent balance of physical properties and price, is widely used commercially. There is on-going research directed to heat resistant copolymers using α-methyl styrene.
For example, copolymers of vinyl cyanide and methyl styrene compounds can have excellent heat resistance. The use of such copolymers, however, can generate a large amount of gas, and thermochromism can occur easily.